User interfaces for sensing human actions and, in accordance with the actions, generating input signals have recently been studied. As an example of such a user interface, a remote control device has been proposed (for example, refer to Japanese Laid-open Patent Publication No. 2013-172211). In this remote control device, a particular object set in advance is used as an input device, and a device to be controlled is manipulated in such a way that the manipulation is dependent on the operation of the operator performed on the input device.
The remote control device disclosed in Japanese Laid-open Patent Publication No. 2013-172211 detects a manipulation operation performed on an input device and, based on the content of the detected manipulation operation and a preset correspondence relationship between the content of the manipulation operation and the content for manipulating the device to be controlled, determines the content for manipulation to the device to be controlled. The remote control device performs, for example, stereo matching of images captured using two cameras arranged in parallel so as to calculate how far the corresponding points between the cameras are from each other on the captured images. From the calculation result, the remote control device determines the distance to a hand of the operator. The remote control device compares this distance with the distance to the input device to determine whether or not the hand of the operator has touched the input device. Using the result of the determination, the remote control device detects a manipulation operation.
As described above, to determine whether or not the operator has touched an object by comparing the distance from the camera to the hand of the operator with the distance from the camera to the object, it is desired that the distance from the camera to the object be measured in advance. Therefore, in the remote control device described above, the distance from the camera to the object is determined by stereo matching. Additionally, there is known a method in which an object to be measured is irradiated with respective ones of a plurality of coded light patterns, and images obtained by capturing images of the irradiated object to be measured at different positions are analyzed, so that the position of the object to be measured is determined (for example, refer to Japanese Laid-open Patent Publication No. 60-152903).